This is actually something which has perplexed me for a long LONG time. The knife itself is a right hand millie from ages ago, well loved, but it was always off center toward the liner-lock side. I could tighten the pivot until it sort of centered itself, but at that point it would require more force to open than I prefer. (I like to be able to flick my knives, and I think Blerv in particular has a hilarious description for my ilk)
I tried all the usual fixes I'd heard floating around the forums, including the often cited loosening/pushing/tightening ritual with the frame screws. No dice. I lived with it though because, at its maximum adjustment and with the pivot slightly tighter than I like it just barely won't scrape the far liner when I go to open it.
My breakthrough came when I caught the clip on a shipping pallet the other day, and bent the clip. Rather than going through the process of ordering another one, I simply took it off and bent it back..... after which point I discovered my blade was almost touching the opposite liner under no force, and always would scrape when I pressed my thumb in the spyder hole and went to open the knife.
Ah ha! The clip somehow, was affecting the centering. I had never thought of that. Why would it after all? After some reflection it occurred to me that, given the clip's unique design and positioning around the pivot, by adjusting it for greater tension, it must have been literally "bending" that side of the knife ever so slightly. The liner, you'll note, is actually quite narrow just below this area as it is cut out to accommodate the liner lock. Reducing the tension of the clip against the liner immediately corrected the issue.
Finally, the last piece of the puzzle: the clip tension on the millie affects its centering. Maybe this was obvious to everyone else, but I couldn't find anyone else suggesting that when an ELU was having centering issues. *shrug* Either way, now my millie is better centered than it came from the factory. :)